Is there an expression that tells AE to automatically trace a specific pre-comp as masks?
by Tara Devlin on Feb 20, 2019 at 8:19:25 pm

Hi Everyone!

I'm trying to automate some versions of a design in After Effects.

I'm using Video Copilot's Saber to react to the silhouette of a person in a pre-comp. The person will change, depending on the version. So, I was wondering if there is an expression that will tell AE to automatically trace this layer as masks?

This is the layer that Saber will react to.

Is that possible?

I hope I explained it properly.

Thanks for any help or guidance.

Best,

Tara

Re: Is there an expression that tells AE to automatically trace a specific pre-comp as masks?by Dan Ebberts on Feb 20, 2019 at 10:19:36 pm

I can't think of any way to do that.

Dan

Re: Is there an expression that tells AE to automatically trace a specific pre-comp as masks?by Kalleheikki Kannisto on Mar 6, 2019 at 10:45:21 am

Are you talking about the silhouette of a face from the side or a silhouette of the full body of a person?

If it is a silhouette of a face, you could use a radial wipe to reveal the outline of the face. You would approach this in a non-mask, non-Saber approach, using the silhouette itself as the starting point. You can get an outline by compositing two copies of the matte, one expanded with minimax and an inverted copy composited on top.

If it is a silhouette of a whole person... I would just use the same mask with the Saber effect for every person and vary the randomity of the effect enough to hide the fact you're not tracing it exactly, revealing the correct shape behind the effect layer.

Kalleheikki Kannisto
Senior Graphic Designer

Re: Is there an expression that tells AE to automatically trace a specific pre-comp as masks?by Alex Printz on Mar 6, 2019 at 4:08:59 pm

can you post some screenshots of what you are looking for? Are you trying to mask the edge of the precomp footage of the mask (essentially a box) or are you trying to automatically mask a complex humanoid shape?

If it is the first (box via footage), I should have the expression for you.

If it is the second (humanoid), no, I don't think there is a way to automate it, you will need to run a rotobrush across the footage.